安装windows/ubuntu之后，默认情况下是启动ubuntu，但是由于近期大部分工作要在windows下面做，所以需要改一下启动顺序，让grub2默认启动windows
笔者ubuntu系统为ubuntu14.04，使用grub2引导，与grub1修改方法可能不一致。这里只讲grub2的修改
原理：修改grub的配置文件/boot/grub/grub.cfg里面的一行set default="0"改为set default="4"即可，数字对应启动第几项，默认0对应第一项，4对应第五项
命令如下：
ls /boot/grub/
sudo gedit /boot/grub/grub.cfg
hadoop@Lenovo-B470:~$ ls /boot/grub/
fonts grub.cfg grubenv locale
gfxblacklist.txt grub.cfg~ i386-pc unicode.pf2
hadoop@Lenovo-B470:~$ sudo gedit /boot/grub/grub.cfg
[sudo] password for hadoop:
(gedit:4494): IBUS-WARNING **: The owner of /home/hadoop/.config/ibus/bus is not root!
(gedit:4494): Gtk-WARNING **: Calling Inhibit failed: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files
(gedit:4494): Gtk-WARNING **: Calling Inhibit failed: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files
在打开的窗口中Ctrl+F 查找set default字符串，笔者找到两项，将其中的set default="0"改为set default="4"
笔者更改后的完整grub.cfg文件如下，请勿直接使用此文件替换
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
set have_grubenv=true
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="4"
fi
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
else
menuentry_id_option=""
fi
export menuentry_id_option
if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi
function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
}
function recordfail {
set recordfail=1
if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi
}
function load_video {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
}
if [ x$feature_default_font_path = xy ] ; then
font=unicode
else
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
font="/usr/share/grub/unicode.pf2"
fi
if loadfont $font ; then
set gfxmode=auto
load_video
insmod gfxterm
set locale_dir=$prefix/locale
set lang=zh_CN
insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
set timeout=-1
else
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=10
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=10
fi
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
if background_color 44,0,30,0; then
clear
fi
### END /etc/grub.d/05_debian_theme ###
### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
set gfxpayload="${1}"
if [ "${1}" = "keep" ]; then
set vt_handoff=vt.handoff=7
else
set vt_handoff=
fi
}
if [ "${recordfail}" != 1 ]; then
if [ -e ${prefix}/gfxblacklist.txt ]; then
if hwmatch ${prefix}/gfxblacklist.txt 3; then
if [ ${match} = 0 ]; then
set linux_gfx_mode=keep
else
set linux_gfx_mode=text
fi
else
set linux_gfx_mode=text
fi
else
set linux_gfx_mode=keep
fi
else
set linux_gfx_mode=text
fi
export linux_gfx_mode
menuentry 'Ubuntu' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
linux /boot/vmlinuz-3.13.0-46-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro quiet splash $vt_handoff
initrd /boot/initrd.img-3.13.0-46-generic
}
submenu 'Ubuntu 高级选项' $menuentry_id_option 'gnulinux-advanced-30b73627-093c-4079-baca-e1a0618ad51a' {
menuentry 'Ubuntu，Linux 3.13.0-46-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-46-generic-advanced-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-46-generic ...'
linux /boot/vmlinuz-3.13.0-46-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro quiet splash $vt_handoff
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-46-generic
}
menuentry 'Ubuntu, with Linux 3.13.0-46-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-46-generic-recovery-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-46-generic ...'
linux /boot/vmlinuz-3.13.0-46-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro recovery nomodeset
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-46-generic
}
menuentry 'Ubuntu，Linux 3.13.0-45-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-45-generic-advanced-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-45-generic ...'
linux /boot/vmlinuz-3.13.0-45-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro quiet splash $vt_handoff
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-45-generic
}
menuentry 'Ubuntu, with Linux 3.13.0-45-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-45-generic-recovery-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-45-generic ...'
linux /boot/vmlinuz-3.13.0-45-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro recovery nomodeset
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-45-generic
}
menuentry 'Ubuntu，Linux 3.13.0-40-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-40-generic-advanced-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-40-generic ...'
linux /boot/vmlinuz-3.13.0-40-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro quiet splash $vt_handoff
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-40-generic
}
menuentry 'Ubuntu, with Linux 3.13.0-40-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-40-generic-recovery-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-40-generic ...'
linux /boot/vmlinuz-3.13.0-40-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro recovery nomodeset
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-40-generic
}
menuentry 'Ubuntu，Linux 3.13.0-35-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-35-generic-advanced-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
gfxmode $linux_gfx_mode
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-35-generic ...'
linux /boot/vmlinuz-3.13.0-35-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro quiet splash $vt_handoff
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-35-generic
}
menuentry 'Ubuntu, with Linux 3.13.0-35-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.13.0-35-generic-recovery-30b73627-093c-4079-baca-e1a0618ad51a' {
recordfail
load_video
insmod gzio
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
echo'载入 Linux 3.13.0-35-generic ...'
linux /boot/vmlinuz-3.13.0-35-generic root=UUID=30b73627-093c-4079-baca-e1a0618ad51a ro recovery nomodeset
echo'载入初始化内存盘...'
initrd /boot/initrd.img-3.13.0-35-generic
}
}
### END /etc/grub.d/10_linux ###
### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###
### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry 'Memory test (memtest86+)' {
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
knetbsd /boot/memtest86+.elf
}
menuentry 'Memory test (memtest86+, serial console 115200)' {
insmod part_msdos
insmod ext2
set root='hd0,msdos8'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos8 --hint-efi=hd0,msdos8 --hint-baremetal=ahci0,msdos8 30b73627-093c-4079-baca-e1a0618ad51a
else
search --no-floppy --fs-uuid --set=root 30b73627-093c-4079-baca-e1a0618ad51a
fi
linux16 /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###
### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Vista (loader) (on /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-chain-FA1CAF751CAF2C17' {
insmod part_msdos
insmod ntfs
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 FA1CAF751CAF2C17
else
search --no-floppy --fs-uuid --set=root FA1CAF751CAF2C17
fi
parttool ${root} hidden-
chainloader +1
}
set timeout_style=menu
if [ "${timeout}" = 0 ]; then
set timeout=10
fi
### END /etc/grub.d/30_os-prober ###
### BEGIN /etc/grub.d/30_uefi-firmware ###
### END /etc/grub.d/30_uefi-firmware ###
### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
### BEGIN /etc/grub.d/41_custom ###
if [ -f ${config_directory}/custom.cfg ]; then
source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
由于每次ubuntu系统更新会执行update-grub2命令，执行之后，默认的启动顺序会还原到ubuntu，所以更新之后需要再次执行上述步骤更改。
Fedora 22/Windows 7双系统：改变默认启动项：http://www.linuxdiyf.com/linux/14546.html
Ubuntu 15.04修改grub默认启动项和Windows 7做双系统：http://www.linuxdiyf.com/linux/12783.html
Ubuntu与Windows双系统默认启动Windows：http://www.linuxdiyf.com/linux/7488.html
CentOS自动登录X11桌面和修改CentOS默认启动：http://www.linuxdiyf.com/linux/4653.html
Fedora 17更改开机默认启动项：http://www.linuxdiyf.com/linux/3412.html